1. Field of the Invention
The present disclosure relates to a method and apparatus for charging a user device wirelessly.
2. Description of the Related Art
Portable terminals now provides a calling function such as a voice call and a video call, a message transmission and reception function such as a short message service (SMS), a multimedia message service (MMS) and an e-mail, and other various functions such as an electronic organizer function, a photographing function, a broadcast replay function, a video replay function, a music replay function, an Internet function, a messenger function and a social network service (SNS) function.
The battery of a portable terminal requires charging, which is divided into wired charging and wireless charging. That is, the portable terminal may be charged in a contact-type charge scheme where the battery is charged by an electric contact or in a contactless charge scheme where the battery is charged using magnetic coupling without an electric contact.
The wired charge method is common. Recently a wireless charging system based on a contactless charge scheme by inductive coupling is being developed. Such a wireless charging system supplies power to a charge pad including a coil (hereinafter, referred to as a “first coil”), and charges a battery using an inductive current generated on a coil (hereinafter, referred to as a “second coil”) included in a portable terminal or a battery due to a magnetic field generated in the coil. That is, the wireless charging system may readily charge the battery by positioning the portable terminal on the charging pad that generates a magnetic field. The charging pad uses a magnetic material core or a winding wire formed on a printed circuit board (PCB).
However, the charging efficiency of the wireless charge system may vary depending on the location relation between the first coil and the second coil. In other words, the best charging efficiency is realized when the first coil is located to correspond to the second coil in the wireless charge system. That is, the wireless charge system requires the user to locate the portable terminal in a designated place to obtain an optimal charging efficiency which may be inconvenient to the user. In order to solve the problem, pluralities of first coils have been mounted or a large-size first coil has been formed to cover the entire area of the charging pad. However, according to this method, the wireless communication performance of the portable terminal is deteriorated due to the influence of the magnetic field generated by the first coil, and the performance and lifespan of parts of the portable terminal may be influenced due to the magnetic field on a high and wide area. Hence, there is a need for a method and system for wirelessly charging a battery capable of securing stability of a portable terminal and optimizing the charging efficiency without deteriorating the wireless communication performance of the portable terminal.
Further, the wireless charge scheme according to the conventional wireless charge system must necessarily include a dedicated charging pad, which is connected to a wall socket using a plug. Hence, in the conventional wireless charge system, the battery of a portable terminal cannot be charged when there is no dedicated charging pad or no power outlet for operating the dedicated charging pad.